This section is intended to introduce the reader to various aspects of art, which may be associated with embodiments of the present invention. This discussion is believed to be helpful in providing the reader with information to facilitate a better understanding of embodiments of the present invention. Accordingly, these statements are to be read in this light, and not necessarily as admissions of prior art.
The world is running out of potable fresh water. Worldwide, an estimated 700 million people cannot obtain enough clean water. In the next 10 years, the number is projected to increase to approximately 1.8 billion. In some regions, obtaining fresh water from seawater may be the only viable way to significantly increase the supply.
In the United States, most of the West coast, especially California, has been in a severe long-term drought. This long-term drought has stressed the water resources of the region. The environmental damage includes damage to the ecology and hydrology from diminishing groundwater and aquifer water resources that are being excessively drained to provide the water requirements of individuals, agriculture and industry. Furthermore, the lack of sufficient water supply is hurting the economy by forcing the region to charge more for water resources and shutting down water intensive industries and businesses.
In the past, desalination plants have been proposed to resolve the fresh water resources problem. Reverse osmosis (“RO”) plants have been delivering desalinated water for decades to regions with limited water resources. However, the high cost to build and operate the RO plants historically made the plants uneconomical for most regions. Accordingly, the major issue of RO technology is that it costs too much. The RO process requires significant energy to force salt water against polymer membranes that have pores small enough to let fresh water through while holding salt ions back.
New plants, using innovative technology, such as, the Sorek plant in Israel have significantly reduced the cost per cubic volume versus conventional desalination plants. The Sorek plant, with a capacity of over 150 million gallons per day of desalinated water, has significantly reduced energy consumption through technological advances and economies of scale using scalable designs. For example, the Sorek plant incorporates several engineering improvements that make it more efficient than previous RO facilities. This technology includes utilizing pressure tubes that are 16 inches in diameter rather than eight inches requiring only a fourth as much piping and other hardware, slashing costs. The facility uses highly efficient pumps and energy recovery devices. In addition, new technologies are being developed such as, advanced membranes made of atom-thick sheets of carbon, that potentially can further reduce the energy requirements of desalination plants.
While this technology has improved the economics of RO desalination, there are still many additional problems to be solved. One problem is the lack of available waterfront land in many regions from overdevelopment along the coastline and developmental restrictions including Not-In-My-Backyard or “NIMBYism.” Offshore desalination has been proposed and desalination has been done on ships. There have been proposals to construct large-scale desalination plants on barges or offshore platforms.
The disposal of the highly concentrated salt brine that contains other chemicals used throughout the process has become a major environmental issue. Large coastal seawater desalination plants discharge brine into oceans and estuaries and therefore, technologies must be developed to provide safe disposal or discharge of brine effluent. Typically, twice as saline as the ocean, the brine discharge is denser than the waters into which brine is discharged and thus, tends to sink and slowly spread along the ocean floor, where there is typically minimal wave energy or currents to mix it. There are several proven methods to disperse concentrated brine, such as multi-port diffusers placed on the discharge pipe to promote mixing. Brine can also be diluted with effluent from a wastewater treatment plant or with cooling water from a power plant or another industrial user. Unfortunately, these approaches have not been shown to reduce the brine concentration sufficiently to prevent serious harm to marine life surrounding the point of discharge.
Accordingly, there is a need to provide offshore desalination, with the ability to efficiently reduce the salinity of the effluent brine discharge to avoid environmental issues for marine ecosystems, including killing marine organisms. In addition, there is a need to further reduce the operating costs including reducing the amount of power necessary to run the plant. Furthermore, there is a need to dilute wastewater offshore from maritime, offshore, and nearshore industrial activities, in addition to, desalination. Wellbores have been used to discharge fluids including contaminated fluids. There is also a need to mix brine in a wellbore to reduce scaling in a reservoir that causes losses in permeability. There is also a need to recapture the energy from the disposal of fluids in a wellbore. The multiple apparatus, method and system embodiments, disclosed herein, solves these needs.